2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.89 



fore it could be cited as a late migrant coming from Honduras across 

 Jamaica to Hispaniola but too late to continue its way to Cuba. 



The classification set forth in this paper is in general along conven- 

 tional lines. One new taxonomic character, which appears to be of 

 some importance, has been introduced. This relates to the structure 

 of the pygidial segment of the abdomen. In the genus Aphodius it 

 will be noticed that the pygidium is more or less uniformly sclero- 

 tized from base to apex, with no transverse ridge or carina and with- 

 out a median longitudinal groove on the basal portion. As a corol- 

 lary, the apical angles of the elytra are individually rounded, not 

 capable of close approximation and without globular thickenings on 

 the under sides at the angles. In the other genera of the West In- 

 dian fauna there is a curious device present that serves to lock the 

 elytra and abdomen together. The pygidium is divided into basal 

 and apical parts, these usually separated by transverse ridge or carina. 

 On the basal part there is a median longitudinal groove of greater or 

 lesser degree of development. The elytra are so constructed that 

 when closed the apical angles are together, and they are so held by 

 virtue of the tongue and grove construction of the sutural edges of 

 the elytra. The apical angles are swollen beneath to form a hemi- 

 spherical knob that is applied to and slides in the groove on the basal 

 part of the pygidium. In some species the transverse carina of the 

 pygidium is somewhat undercut to accommodate the apical edges 

 of the elytra. This condition is found in many other genera of 

 the Scarabaeidae, as Ghoeridiwm and Phanaeus. It is therefore a 

 secondary modification that has arisen independently in the various 

 groups. But within the Aphodiinae it would appear to be of some 

 value as an indication of the close relation existing between certain 

 tribes. Thus the Aphodiinae and Corythoderini seem to be mutually 

 allied and to a degree separated from the Eupariini, Psammodiini, 

 and Rhyparini. 



This revision is the result of a study of more than 6,000 specimens 

 from 20 of the West Indian Islands. The greater part of this ma- 

 terial was secured during the years 1935 to 1937 by Dr. and Mrs. R. 

 E. Blackwelder, while Dr. Blackwelder was the holder of the Walter 

 Rathbone Bacon Scholarship of the Smithsonian Institution. To 

 their collections have been added the specimens already in the United 

 States National Museum, smaller lots from St. Croix submitted by 

 H. A. Beatty, from Puerto Rico, collected by the late Stuart T. Dan- 

 f orth, and a fair collection from Jamaica made by the writer in 1937 

 while associated with Dr. and Mrs, Blackwelder. This probably is 

 a greater mass of material than has been available to any previous 

 worker. Thanks are offered to these and others, notably to G. J. 

 Arrow, of the British Museum, for loan of specimens; to H. E. Hin- 



